Guarantees Mortgage Loans Repurchase Reserve Rollforward (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Guarantees [Abstract]
Reserve For Mortgage Loan Repurchase Losses	$ 59	$ 77	$ 59	$ 77	$ 60	$ 85	$ 77	$ 78
Mortgage Repurchase Reserve, Provision for Mortgage Loan Repurchase Losses	(1)	(2)	(9)	(12)
Charge Offs For Mortgage Loan Repurchase Losses	$ 0	$ 2	$ 17	$ 13